"if it was a snake, it would have bitten you"的定义和意义

What is the origin of the idiom "if it was a snake, it would have bitten you" and when to use it?

The origin of the idiom "if it was a snake, it would have bitten you" is not well-documented, but it is believed to be of American origin. The imagery of a snake biting someone serves as a metaphor for the idea that someone has failed to notice or find something that is very obvious and nearby.